Effects of interface modification on electrical and optoelectronic properties of p-type CuAlO2/n-type Si heterojunction devices

The effect of interface modification on the electrical properties of heterojunction diodes based on the p-type CuAlO 2 and n-type Si is investigated. Compared with the CuAlO 2 /Si device without H 2 O 2 treatment, the CuAlO 2 /Si device with H 2 O 2 treatment exhibits a better rectification behavior. The forward-bias current–voltage characteristics can be explained on the basis of the space charge limited current theory for CuAlO 2 /Si device without H 2 O 2 treatment. However, the thermionic emission model is the dominant process in this fabricated CuAlO 2 /Si device with H 2 O 2 treatment. The enhanced device performance is mainly the result of the formation of Si–O bonds that serves to reduce the number of interface states. The effect of H 2 O 2 treatment on the sensitivity to solar irradiation and the response time for CuAlO 2 /Si devices is also studied. An increase in the values of photocurrent and photosensitivity is attributed to the rectification performance improvement that results from interface passivation.